Widespread Coronavirus infection found in Iowa Deer, new study says

Penn State researchers have been working with the Iowa Department of Natural Resources, which already performs monitoring of chronic wasting disease, a deadly neurological disease among white-tailed deer. The first positive test results appeared in September 2020 – in two deer at each end of the state. Between late November and early January, when the pandemic increased in people across Iowa, 80 percent of deer samples tested positive for the virus.

At that time, the researchers had tested only 300 of the 5,000 lymph nodes available to them; but the evidence was overwhelming.

Such a high infection rate, said Dr. Kuchipudi, in fact, was 50 times greater than its prevalence among Iowa’s human inhabitants during the height of the pandemic.

What they found as they searched deeper was even more astonishing. Using tests to decode the genomic composition of each viral sample, they found similar patterns between the emergence of mutations and variants in the deer population of the state and those that infected humans. Researchers said it provided stronger evidence of human-to-deer transmission as well as evidence that deer then spread the virus to each other by a quick clip. Mapping the location of each sample also indicated that the infections occurred simultaneously throughout the state as the hunting season increased. The study’s authors say it is unclear whether the deer became ill from the infection.

How the virus is transmitted from humans to deer, however, is not entirely clear. Rachel Ruden, Iowa’s state veterinarian and author of the study, said there were plenty of opportunities for transfer as 445,000 deer roamed the state.

The virus can be spread when people feed deer in their backyard, through sewage discharges or perhaps when an animal licks a blob of chewing tobacco left behind by an infected hunter. “Maybe it doesn’t take much of a loading dose to get deer infected,” she said. “But no matter what, all of this is a striking example of us all being in this pandemic together.”

The study raises a wide range of questions that researchers will be eager to investigate, including whether other wildlife can also carry the virus, especially rodents such as mice that live in even closer proximity to humans. The more species that are able to carry the virus, the greater the chances that it can evolve in ways that threaten human health.

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